U.S. Pat. No. 5,163,345 discloses a nut driver with a tubular shank having a socket coupled to one end thereof for receiving an associated rotatable fastener, such as a nut. The nut driver has an elongated hollow tubular shank, an elongated handle attached to one end of the shank and a socket attached to the other end of the shank. The shank has a cylindrical external surface, and a cylindrical internal surface which defines a bore formed axially through the shank. The elongated handle has a blind bore formed axially therein at one end thereof. In use, the inner end of the tubular shank is received into the blind bore in the handle and fixed thereto by suitable means. The socket is a generally cylindrical member having an axial bore provided therethrough with an enlarged-diameter counterbore portion at the inner end thereof, which is dimensioned for receiving therein the outer end of the shank. The socket is fixedly secured to the shank. The bore of the socket is provided with a receptacle for mateably receiving the rotatable fastener. The receptacle defines an annular shoulder at the inner end thereof against which one of the faces of the rotatable fastener seats in use. A helical compression spring is mounted in the bore of the shank and has an outer end that is coupled to a magnetic assembly, which is known in the art. The magnetic assembly bears against the inner face of the rotatable fastener to magnetically retain the rotatable fastener in the receptacle. In operation, when the rotatable fastener is driven onto the shank of an associated bolt, the tip of the bolt shank engages the magnetic assembly and compresses the spring for thereby accommodating the shank of the bolt in the shank of the nut driver. Thus, the rotatable fastener may be driven for a considerable distance onto the shank of the associated bolt.
The magnetic assembly is costly to manufacture since it requires so many components that must be made and assembled. In addition, the magnetic assembly tends to collect metallic debris that can clog the socket making insertion of a nut difficult.
U.S. Pat. No. 6,045,311 discloses a nut driver for use with a tapered nut. The nut has a tapered, polygonal nut body, an axial coupling hole defined within the nut body, and an inner thread provided on the inside of the nut body around the axial coupling hole. The nut body has a tapered, polygonal outside wall axially inwardly sloping from a front end thereof toward a rear end thereof. The driver has a socket integral with one end of a shaft thereof. The socket has a tapered, polygonal coupling hole for coupling to the tapered, polygonal nut body of the nut, permitting the nut to be turned with the driver. The coupling hole tapers from the front end of the socket to the rear end of the socket. The driver in U.S. Pat. No. 6,045,311 uses a taper lock. The nut and the driver both have the identical slight taper. Because both the nut and socket are tapered, the “lock” is so severe that the lock makes removal of the nut from the socket extremely difficult.
The present invention provides a driver for rotatably driving a threaded fastening member which overcomes the problems presented in the prior art and which provides additional advantages over the prior art, such advantages will become clear upon a reading of the attached specification in combination with a study of the drawings.